The invention relates to a milking device provided with cleansing means, in particular for cleansing/disinfecting the teat to which the milking device is connected. The invention furthermore relates to a method for cleansing the teats of an udder after milking.
From German patent application 26 22 794 such a device and method are known. This document shows a milking device for pneumatically milking a cow and the subsequent cleansing or disinfecting the teats of the cow""s udder, with a system of four milk extractors, each comprising a teat cup which at one end is provided with an open lining and with the other end is connected to a milk line to a common milk collection chamber for the milk from the cow concerned, each cup having a connection to a source of changing underpressure, and an outflow opening of a line for the supply of cleansing liquid being arranged in the wall of a teat cup.
When using this known device the method used is to first place the teat cups around the cow""s teats, after which the cow is milked with the help of the changing underpressure. After finishing milking the cow, while the cow""s teats are still in the teat cups, a certain quantity of cleansing liquid is squirted into the teat cup with the help of a pump. Said liquid will disinfect the teat and the space in the teat cup, but will subsequently together with the milk residue in the teat cup deposit on the inner wall of the teat cup. The liquid will then have the chance, even before the teat cups have been removed from the teats, to go back past the inner wall or from the teat back down and thus partially end up in the milk line. As a result not only milk residues of a cow will be left in the teat cup and milk line but also transfer a contamination from the one cow to the other. Moreover, when milking the next cow residues of the cleansing liquid that have ended up in the milk line will end up in the central milk storage to which it is connected and therefore in the milk to be delivered.
An object of the invention is to provide a device and a method with which this is prevented.
From one aspect the invention to that end provides a device for pneumatically milking a cow, comprising a number of milk extractors, each comprising a teat cup as well as a milk line connected to the lower end of the teat cup, which leads from the teat cup to a collection chamber for the milk from the teat cups, each milk extractor being provided with a supply for a cleansing medium, such as a disinfectant, to the teat cup, in particular to the teat present in the teat cup, the supply comprising a line which at the location of an outlet debouches into the milk extractor, in particular the milk line, and each milk extractor being provided with means for closing off the milk extractor near or downstream of the outlet, preferably at that level, when discharging the cleansing medium through the outlet.
Thus, when discharging cleansing medium, and the aforementioned problem therefore exists, it is prevented that during discharging the cleansing medium, said medium can end up in the milk line and thus in the milk collection chamber.
The supply line for cleansing medium can have its outlet in the teat cup, but preferably, in the milk line, preferably as close as possible near the lower end of the teat cup. Preferably the closing means are arranged near the transition of the teat cup to the milk line, so that the portion of the milk line in which cleansing medium could possibly end up is as short as possible. The path the cleansing medium has to take in order to get into the teat cup can also be as short as possible.
Preferably, the closing means close off the supply line when in the deactivated position, so that entrance of milk therein is prevented. Preferably the closing means close off the outlet of the supply line when in the deactivated position, so that there are no blind spots present in which the milk may end up.
Preferably, the closing means comprise a closing body, which can reciprocate between a milking position in which it closes off the outlet and a cleansing position in which it closes off the milk extractor. Thus the one passage (for cleansing medium) and the other passage (to the milk collection chamber) is closed off/opened alternatingly with one single body.
Preferably, the closing body has planes for guiding the cleansing medium in the milk extractor in the direction of the teat cup, the supply line preferably debouching with a component in the direction towards the teat. In this way the closing body performs an additional function. These planes can also cooperate in the guidance of cleansing medium falling back to the supply line, where it can do no harm.
In order to promote the milk extractor to become open after the cleansing of andxe2x80x94possiblyxe2x80x94the disconnection from the teat, means are furthermore preferably provided for biassing the closing body in the cleansing position towards the milking position.
Preferably, the closing body comprises an elastically flexible strip of material fixed at one end, which can be moved from the milking position to the cleansing position by bending. Preferably the elastically flexible strip is attached in the milk extractor, in particular in the milk line, near or downstream of the outlet, such as in a coupling piece between the teat cup and the rest of the milk line.
Preferably, a seat is placed in the milk extractor for sealing support of the closing body in the cleansing position, the seat preferably having a curved course in accordance with the bend line of the closing body. The closing body can thenxe2x80x94freely or urged, see belowxe2x80x94move towards or from the cleansing position, but provide an optimal sealing in the cleansing position.
Preferably, the seat is formed in the wall of the milk extractor, particularly in the milk line, so that the number of parts can be kept limited and moreover slits and holes in which milk could be left behind are prevented.
A simple and long term reliably working embodiment of the closing body is the one in which the strip is made of metal, particularly being a leaf spring.
The device according to the invention is preferably provided with operating means for the closing means, as well as control means for controlling the operating means in dependency of the discharge of the cleansing medium.
According to a further development of the device according to the invention, the operating means comprise an operating member, which can be moved between an active position which puts the closing means in the cleansing or closing position and a rest position. In this way it is promoted that the closing means can close off the milk line in a certain manner, for as long such is desired.
Preferably, the operating member, when in the active position, is accommodated to urge the closing means to the closing position, preferably against a returning force. The closing means are thus kept in the closing position in a positive manner, for as long such is desired. After that the returning force can be utilized for automatic clearance of the passage in the milk line.
Preferably, the operating member is in press contact with the closing means, which makes simple constructive arrangements possible. Such a arrangement may for instance be one in which the operating means comprise a pusher member and the closing means comprise a closing body which, at least in the rest position, is biassed towards the operating member.
Constructive simplicity is further promoted when the operating member and the outlet of the supply line are located on the same side of the milk extractor.
In this development the control means are advantageously adapted for activating means for pressurizing the supply line simultaneously with or shortly after activating the operating means for the closing means. The operation of the supply line and the discharge of cleansing medium will take place most reliably when the control means are adapted for activating the means for pressurizing the supply line shortly after activating the operating means for the closing means.
The closing means can also be adapted for activation by a rise of pressure in the supply line.
In the development with operating means discussed above, it is however preferred that the operating means comprise an operating line, for instance pneumatic, which is separate from the supply line, so that for supply line and for closing means the optimal operation means can always be designed.
In an alternative, further development of the device according to the invention, the operating means comprise an operating line, for instance pneumatic, which coincides with the supply line and for operation of both use can be made of the same pressure source. The closing means can then for instance be designed for activation as a result of a rise in pressure in the supply line.
Thus when discharging cleansing medium, and the aforementioned problem therefore being present, in a manner directly controlled by the rise in pressurexe2x80x94in connection with said dischargingxe2x80x94it is prevented that during discharging the cleansing medium, said medium ends up in the milk line and therewith in the milk collector chamber.
The invention further relates to an assembly of a number of devices according to the invention and to a central milk storage connected to the milk collection chamber.
From another aspect, the invention provides a method for cleansing and/or disinfecting the teats of a cow""s udder, after the cow has been milked with the help of a device for pneumatically milking a cow, which device comprises a milk collection chamber and a system of milk extractors, which each comprise a teat cup and a milk line extending between the teat cup concerned and the milk collection chamber, wherein immediately after milking has ended, but before the teat cup is removed from the teat a certain quantity of cleansing liquid is introduced into the teat cup, via a supply line and an outlet thereof in the milk extractor, and simultaneously or shortly after the milk extractor, in particular the milk line, is closed off near or downstream of the outlet of the supply line.
Preferably, the milk extractor is then closed off at the level of the outlet.
Preferably, the cleansing liquid is supplied with a pressurized carrier gas, such as air, during a certain period of time, which is of such a length, that the gas flow, first blows the cleansing liquid into the teat cup and subsequently blows the contents of the teat cup to the outside, so that the teat cup comes free from the teat, the milk extractor being kept closed off downstream of the outlet at least until the teat cup comes free. During the pressure blast, which causes a counter pressure wave in the direction of the teat cup and therewith a returning transport of cleansing medium, its entrance in the milk extractor, in particular the milk line, is prevented by its closing off, and namely as long as the pressure is on the teat cup. After disconnecting there is no longer danger of flowing back of cleansing medium.
Preferably, the end of the certain period of time that the gas flow is kept going is more or less the same as the moment, that the teat cup is tilted half a turn after the teat cup has come entirely free from the teat, preferably approximately 5 seconds.
Preferably, the certain quantity of cleansing or disinfecting liquid is 5 to 7 cc.
Preferably, the closing off of the milk extractor takes place with the help of a closing body, which is urged into a cleansing position which closes off the milk extractor by the gas flow or by a separate operating means. Preferably the closing member closes off the outlet when there is no gas flow.
From another aspect, the application has the object to provide a method, as a result of which the teats of a cow""s udder are cleansed well and as much residue of milk left behind and the introduced cleansing liquid as possible are removed from the teat cup such that it cannot end up in the milk.
To that end the application provides a method for cleansing and/or disinfecting the teats of a cow""s udder, after the cow has been milked with the help of a device for pneumatically milking a cow, which device comprises a system of teat cups which are each connected to a milk line, a cleansing liquid being introduced into the teat cup via a line and an inflow opening, which method comprises the introduction of a certain quantity of cleansing liquid immediately after the milking has ended, but before the teat cups have been removed from the teats with the help of means via an outflow opening, which outflow opening corresponds with the inflow opening for the liquid in the teat cup, the means consisting of a gas flow, such as an air flow, which is blown or squirted into the teat cup under pressure via the outflow opening during a certain period of time, the period of time being such that the air flow first blows the cleansing liquid into the teat cup and pressurizes the space in there and preferably subsequently blows the contents of the teat cup to the outside, which promotes the release of the teat cup.
According to this method, the cleansing liquid will spread over the space between the teat and the teat cup and keep the space under a certain pressure until the release of the teat cup, as a result of which the teat cup can easily be detached from the teat. It appeared that the air flow blows the milk residues which are left behind in the teat cup after milking, together with the surplus of cleansing liquid to the outside.
Preferably, the cleansing liquid is squirted in an aimed manner into the direction of the axis of symmetry of the teat cup. In this way it is achieved that first the teat is cleansed from the milk residues and subsequently these milk residues with the cleansing liquid are blown to the outside via the inner wall of the teat cup.
In a further development thereof, the application provides a device with which it is achieved in the optimal sense that the cleansing liquid ends up on the teat end of the cow. To that end the application provides a device for pneumatically milking a cow, comprising a system of teat cups which each are provided with an open lining at one end and with their other end are connected to a milk line, each cup comprising a connection to a source with changing underpressure, and in which a cleansing medium, such as a disinfecting liquid, can be introduced into the tea cup via an inflow opening which is the outflow opening of a line for the supply of the cleansing liquid, the outflow opening for the cleansing medium being provided with a tube-shaped member, of which the centre line is more or less parallel to the axis of symmetry of the teat cup and of which the outflow opening is directed towards the end of a cow""s teat present in the teat cup during use.
With these measures it is achieved that first, the end of a cow""s teat is sprayed with the liquid, as a result of which milk residues that are still hanging at the lower end of the udder are blown away and subsequently with the upward air flow along the outside of the udder and the wall of the teat cup to the open upper side of the teat cup and subsequently to the outside out of the space of the teat cup after it has been released from the teat. In this way the entire inside of the teat cup and the cow""s teat are cleansed well and disinfected and all milk residues are efficiently removed from the teat cup at the end of a milking course. The milk residues that have ended up on the inside of the teat cup when the teat is spray cleansed, and the milk residues left there when milking can thus be removed from the teat cup, so that there is no danger of contamination for the next cow to be milked, if the milked cow should have an infection.
Preferably the device according to the invention is constructed such that a supply line for the supply of the cleansing liquid is arranged in the wall of each milk line near the transition to the teat cup and the tube-shaped part of the tube-shaped member along the wall of the milk line runs parallel to the axis of symmetry of the teat cup. From applicant""s European patent EP 0 543 463 a device for pneumatically milking a cow is known per se, which device is provided with means for cleansing the inside of the teat cup subsequent to milking, comprising a system of teat cups which each are provided with an open lining at one end and with their other ends are connected to a milk line, each cup comprising a connection to a source with changing underpressure, and in which an outflow opening of a line for the supply of cleansing liquid is arranged in the wall of each milk line near the transition to the teat cup. The liquid flow here however is directed at the wall of the teat cup.
Preferably, the member is a tube which connects to the outflow opening of the supply line and which is mainly pressed flat and abuts the inside of the milk line and in which a closing valve is arranged in the outflow opening of the supply line. This embodiment is easy and simple to apply by first, in the known manner as indicated in applicant""s European patent EP 0 543 463, providing a supply line with a closing valve in the wall of the milk line which supply line is already provided with a pipe arranged in line with the supply line which pipe is contiguous to the outflow opening and subsequently with help of a mandrel pressing the pipe flat against the wall of the milk line. Because the pipe will spring back a little the pipe will exactly take the wanted position, the outflow of the gas and the cleansing liquid exactly being directed at the end of the cow""s teat when said teat is in the teat cup.
Preferably, a closing valve is arranged in the outflow opening of the supply line, so that no milk can come into the supply line for the cleansing liquid and moreover no cleansing liquid can flow out of the supply line if not under a certain pressure.
According to a preferred embodiment, the first closing valve is arranged in a connecting piece, which is accommodated in a first branch of the milk line. In this way the supply line for the cleansing liquid is separated from the milk line and the supply line can easily be connected to and disconnected from the milk line, for instance with maintenance or repair.
Preferably, the branch with connecting piece is part of a coupling piece, which can be coupled between the teat cup and the milk line. In this way a separate part is provided which can be placed under the teat cup in the milk line and to which the supply line for the cleansing liquid can be connected. In this manner the milk line is modular, and the coupling piece can easily be replaced, for instance when the closing valve does not function well. It is also possible to arrange such a provision in already existing devices for mechanical milking of cows.
The invention also relates to a coupling piece as described above.